Be careful with this chip though. It seems to oscillate very easily. I have made an amplifier with this one using the TIP142/147 darlingtons as driver. They didn't seem to be too happy with clipping though, but I have a feeling that has something to do with the fact I didn't put protection diodes on the drivers...
Take a look at my schematic. I also have the pcb's for that one.

Haven't got a clue. I gave up working on this project because I assumed it was limited to using darlingtons. Besides I don't like the tda7250 at all. It produced quite a lot of hum with me, and with this sort of ic's.. where do you begin looking eh?
I'm going to take my chanches with the TDA7293 wich seems to be a lot easier and compact...

That TDA7250 thing doesn't really make sense to me. With +/-45V supply rails ypu can add as much output devices as you want, the 4 ohm power won't increase.
The only chance to get reasonable more power ist to use the both amplifiers in bridge mode.
I haven't read the specs of the TDA, nor have I looked at the DPW666 solution, but I would say that a good discrete front end won't make such a big amplifier much more expensive.
So why stick to that limited driver chip?
---
Holger